The prime minister and besieged Natural Resources Minister Lisa Raitt stood firm against a torrent of calls Tuesday that she step down, a day after a recording was unveiled in which Raitt called the isotope shortage a "sexy" issue that could earn her political points.

On day two of the widening scandal, opposition parties and cancer patients upped their attacks on Raitt and demanded that she be fired for her statements, which were made during a private conversation with a former aide.

Despite intense pressure, however, both Raitt and Stephen Harper refused to give an inch as both stopped short of even issuing a formal apology.

"This minister has been working around the clock to make sure we get a greater supply of isotopes and make sure we have alternative options for our health-care patients in this country," Harper said in Parliament.

Harper also lashed out at the opposition and accused them of playing "cheap politics."

Harper defended Raitt's work on the medical isotope file, saying she was working with the international community to improve the isotope supply in the medium and long term.

"That's what the minister is doing, that's what this government is doing, not playing cheap politics."

On the tape, which was apparently recorded by mistake in January by Raitt's former press secretary Jasmine MacDonnell, the minister is also heard questioning the competency of Health Minister Leona Aglukkaq.

While the NDP, Bloc Quebecois and Liberals all called in unison for Raitt's resignation, politicians weren't the only Canadians crying foul Wednesday.

New Brunswick resident Geraldine Owen, whose daughter-in-law is battling breast cancer, said Raitt's comments were hurtful and callous.

"How could she?" Owen, 67, told The Canadian Press. "There is nothing sexy about cancer."

The tape was made public by the Halifax Chronicle Herald on Monday, only a few days after MacDonnell was sacked for leaving sensitive government documents at Â鶹´«Ã½' Ottawa bureau.

Comments turn to political scandal

Liberal Leader Michael Ignatieff responded that Raitt has failed to get the isotope shortage under control as the minister in charge of the file.

"The cheapest politics there is is to call a crisis a career opportunity," Ignatieff said. "This is about the minister's performance. The government knows there aren't enough isotopes."

NDP Leader Jack Layton said at the very least Raitt should apologize, if not step down, for comments that are insensitive to cancer patients who may have to wait longer for tests or treatments due to the isotope crisis.

"Not only is the minister losing secret documents, she expected a career bounce as a result of a medical crisis. And this is a crisis in a ministry for which she is ultimately responsible," Layton said.

Earlier Tuesday, a spokesperson for Harper called Raitt a "very intelligent, very competent minister" whose private comments with her communications director Jasmine MacDonnell were taken out of context.

"I don't think anyone believes there is any political gain to be had from dealing with what is a very serious health crisis," Kory Teneycke told Â鶹´«Ã½ Channel.

Teneycke said the minister remains focused on getting the Chalk River nuclear reactor back in operation to once again produce isotopes used in medical imaging.

The contents of the tape were released after the Chronicle Herald won a court battle on Monday to publish the information.

The recording of the conversation between Raitt and MacDonnell was left in a bathroom in the House of Commons and eventually fell into the hands of Steve Maher of the Chronicle Herald, who held off from listening to it for months.

Maher told CTV's Power Play Tuesday that he had called MacDonnell months ago after first receiving the tape, to tell her that he had it. They exchanged emails and phone calls, but she never actually came to pick it up.

When he finally listened to the tape and heard Raitt's controversial remarks, he gave MacDonnell the heads up.