"Equal work, equal pay" is a key plank in the raft of economic policies that Japanese Prime Minister Shinzo Abe has vowed to implement in the run-up to the Upper House election tomorrow.

With irregular part-time workers making up 40 per cent - a record high- of the workforce, political parties are paying more attention to their concerns.

Here is a look at the safeguards for part-time workers in other countries.

SINGAPORE: Contract workers who work in the same firm for at least three months are entitled to statutory leave benefits, under new guidelines issued last month.

Some 11 per cent of Singapore's resident workforce was employed on term contracts last year.

The Employment Act sets minimum standards for all contracts, regardless of part-time or full-time.

CHINA: Wages must be paid every two weeks for part-time employees under laws enacted in 2008, and should not be below the minimum wage set by local governments.

The law defines part-time workers as those who work less than 24 hours a week.

SOUTH KOREA: Terms and conditions for part-time workers must be proportionate to that of full-time workers engaged in the same job, based on their working hours. The law bans fixed-term contracts of more than two years.

UNITED STATES: The employment law does not specifically cover part-time workers, who number at least six million.

As such, they are often paid less per hour than full-time workers, and often do not enjoy health benefits or paid time off.

FRANCE: Temporary contracts should be less than 18 months, and workers are entitled to the same rights as full-time employees, including leave benefits.