Parliament's health select committee was considering a 5000-signature petition presented by Mr Walker which calls for the decision to downgrade Lumsden from a primary birthing unit to a maternal and child hub to be reconsidered.
''To put that in context, the population of Lumsden is about 200,'' Mr Walker told the committee.
The SDHB opted to change Lumsden's status as part of a region-wide reconsideration of maternity services and where they should be based.
The downgrade decision takes effect on April 15, so Mr Walker's petition, which calls on the committee to investigate the decision, represents the final chance to avert the process taking place.
''This decision will have severe consequences for the rural Southland community, with the increase in risk of complications for mothers and babies during birth - blood I would hope no-one wants on their hands,'' Mr Walker said.
''Downgrading the centre doesn't take away the fact women in rural Southland will need a place to give birth.
''It means their health and safety is put at risk and the distance they have to travel is further.''
Mr Walker's other main points in support of his petition were the effect midwives leaving Lumsden might have on the wider regional economy and the impact the downgrade would have on first responders.
Mr Walker also questioned the numbers used by the SDHB to reach its decision.
He said the board had relied on the number of births in the area annually, when it should have instead considered the number of pregnancies, which was a much larger number.
The committee was also briefed by Ministry of Health principal maternity adviser Bronwen Pelvin, who said it had confidence in the SDHB's process and figures.
''Services, particularly in rural New Zealand, when there looks to be a reconfiguration, it causes a lot of angst and heartache,'' she said.
''The SDHB did do a lot of work in terms of coming up with their plan for an integrated primary maternity system across the whole of their ... region, and we recognise the difficulties for a DHB in considering how they are going to provide services or contract services.''
