Home Secretary Priti Patel has repeatedly refused to appear in front of a select committee to discuss the coronavirus outbreak.
Ms Patel has turned down four invitations to appear before the Home Affairs Committee since January, offering private briefings instead.
In a letter, Ms Patel she would attend “towards the end of the month”.
In an interview with TalkRadio on Thursday, the home secretary said there was "politicking going on".
She said: "It's a bit disappointing at the time of the crisis when I've already offered a date as well that there is a bit of politicking going on...I just think it's just politics basically."
BBC Home Affairs correspondent Danny Shaw described the letters between Ms Patel and Labour's Yvette Cooper as “acrimonious”.
Ms Patel was appointed by Boris Johnson as home secretary in July 2019, but has only appeared in front of the committee once - in October.
On Wednesday, a Home Office spokesperson said the home secretary "has already offered to appear before the committee at the first mutually convenient date to update them on her work to keep the country safe during this unprecedented time."
Ms Patel "is currently leading the Home Office response during this national crisis, working tirelessly to keep the British public safe," the spokesperson added.
Ms Cooper wrote to the home secretary on 3 April.
She told Ms Patel the committee had set a date of 15 April to hear evidence from her, saying “there is no reason for further delay”.
But four days later, the home secretary responded, writing: “I am disappointed at the increasingly adversarial tone of our exchanges.”
Ms Patel instead said she would only appear “towards the end of the month”.
Ms Cooper has now written again, saying other secretaries of state have appeared regularly before other committees - but she has yet to receive a reply.