It's not okay to pressure someone into having another drink, says Whanganui District Health Board.
The DHB is encouraging people to drink alcohol responsibly over the Christmas and New Year period.
It is urging people to actively encourage drinking moderately.
"Show support and back your friends who are trying to ease up on the drink this summer," said the DHB's alcohol and other drugs health promotion officer, Chester Penaflor.
"If you know someone who is trying to reduce their drinking, please support them. It is socially acceptable to say 'no more' and to not be pressured to have 'another one'."
Penaflor said the current recommendation was that women drink no more than two standard drinks a day, while for men it was three. It is also recommended people have at least two alcohol-free days a week.
The health promotion officer also warned there was no safe time to drink for pregnant women.
"That's the message for pregnant women, their partners and their families, who have an important role to play in supporting alcohol-free pregnancies. It falls upon all of us to look after the health of our babies-to-be."
The safe-drinking message was also relevant for older and younger Whanganui District residents, Penaflor added.
Older adults tended to experience worse side-effects from alcohol use, and no alcohol was still the safest option for people under the age of 18.
"Another important point to remember is, when supplying alcohol to those under the age of 18, you need to obtain consent from that person's parent/legal guardian or you might find yourself paying up to $2000 in fines," Penaflor said.
"When it comes to having a good time, use simple harm reduction tools such as drinking water in between drinks or choosing low-alcohol drinks. It helps you enjoy the occasion - and remember it."
*If you find it hard to stop drinking or to cut back, talk to someone you trust or call the Alcohol Drug Helpline on 0800 787 797.