Small Business Minister Nick Sherry announced on Monday his resignation ahead of a cabinet reshuffle. The senator from Tasmania said he would no longer run for reelection.

"I do think it is important from time to time that the executive in any business or government is refreshed," The Australian quoted Mr Sherry.

The minister said he has been in public service for a long time and his turning 56 is a good opportunity to step down from office and spend time with his three young children because government work has made it difficult for him to balance work and family life. Mr Sherry pointed out that he has served four Labor prime ministers and three other Labor leaders.

Mr Sherry said he hoped he will be replaced by another Tasmanian. Reports said that he will likely be replaced by his parliamentary secretary, Julie Collins.

"It is certainly appropriate that there be a Tasmanian, at least one Tasmanian, on the frontbench, for obvious reasons," Mr Sherry said.

His term in the Senate is supposed to end June 30, 2014.

Prime Minister Julia Gillard will announce the reshuffle of her cabinet by noon. Assistant Treasurer Bill Shorten is touted to become workplace minister, while Health Minister Nicola Roxon is expected to be designated attorney-general.

However, Industry Minister Kim Carr and Senate Leader Chris Evans are reportedly being demoted.