Over 5 million people traveled across China by train on New Year's Day this year, the Ministry of Railways (MOR) said Monday.

Increasing numbers of mid-and short-distance travelers contributed to the heavy traffic, according to the MOR.

A total of 137 temporary trains were put into service on Sunday, the first day of the three-day New Year holiday, the MOR said.

The MOR will put 152 temporary trains into service on Monday to accomodate travelers' needs during the holiday.

Several passengers have complained about the instability of the ministry's newly-launched online ticketing system, which has at times failed to issue tickets that were already paid for.

The MOR said the system has a 30-minute limit for payment processing, with tickets returned to the purchasing pool after the limit is exceeded.

The ministry said the time limit was extended on Saturday, adding that customers who have not received the tickets they purchased will have the cost of the tickets credited to their bank accounts within 15 days.