ACL Tasmanian Director Mark Brown said just one sitting Labor MP, Brian Wightman, participated in the five Meet Your Candidate Forums conducted by the lobby.
"In comparison, seven sitting Liberal MPs and three sitting Greens MPs attended," he said.
"There will be many Christian Labor voters who are disappointed that their sitting Labor member was not pro-active about engaging them," Mr Brown said.
Mr Brown said Labor had proud historical roots in Christianity amongst Irish Catholic workers and Protestant Methodists who were at the forefront of the creation of the trade union movement.
"Given the comments by party leader Bill Shorten over the weekend regarding the need for the ALP to be growing its membership, the Tasmanian Labor Party should not neglect reaching out to Labor voters among the Christian constituency," he said.
"According to the latest census data, 60 per cent of Tasmanians profess a Christian faith, many who are being actively engaged on political issues," he said.
"In fact, Catholic Archbishop Julian Porteous last week sent out a letter to the Catholic community encouraging parishioners to think carefully about candidates' views on social issues ahead of the March 15th election," Mr Brown said.
Archbishop Porteous encouraged people to be informed via two websites, including www.tasvotes.org.au site which has a printable conscience vote history table which clearly shows differences in candidates' views on the social issues mentioned in the letter.
The total number of candidates attending the five ACL Meet Your Candidate Forums, including sitting members, were nine for the Labor Party, 15 from the Liberal Party, nine Greens, eight Palmer United Party, four Nationals, two Australian Christians and three independents