Labor says the coming week of federal parliament will show how the government has a set of wrong priorities.
Draft laws to cut the corporate tax rate for all companies from 30 per cent to 25 per cent are due to be debated in the Senate on Monday.
Prime Minister Malcolm Turnbull wants the parliament to vote on the tax cut by the end of the week, which is the last sitting before the long winter break.
The government is still short the extra votes it needs to get the bill passed and will be negotiating with One Nation and other crossbenchers.
At the same time the banking royal commission is due to hear more evidence of misconduct in its hearings in Brisbane.
Labor deputy leader Tanya Plibersek says the timing of the tax cut shows "another set of wrong priorities".
"We'll see a government giving a $17 billion tax cut to the big banks if they get their proposal through, at a time when we're watching week after week of disclosure from the banking royal commission about the poor behaviour of the big banks," she said.
Liberal frontbencher Christopher Pyne said the government remained committed to the tax cut, but declined to comment on talks with One Nation.
"The Senate will have an opportunity this week to vote for it."
Pauline Hanson has said she won't support company tax cuts unless the government can convince her it is properly tackling multinational tax avoidance.