diff --git a/pglite/build-postgis.sh b/pglite/build-postgis.sh
index 5ff083c17d50d..5e5c092175901 100755
--- a/pglite/build-postgis.sh
+++ b/pglite/build-postgis.sh
@@ -12,9 +12,11 @@ PROJ_VERSION=9.7.0 LDFLAGS="-L/install/libs/lib" CFLAGS="${PGLITE_CFLAGS}" CXXFL
 # touch ./loader/pgsql2shp.wasm
 emmake make raster-sql || true
 # these flags are used in pgxs.mk (postgresql extension makefile) and passed to the build process of that extension
-emmake make LDFLAGS_SL="-sWASM_BIGINT -sSIDE_MODULE=1 -fexceptions -Wl,--whole-archive -lstdc++ -lsqlite3 -lgeos -Wl,--no-whole-archive" \
-CFLAGS_SL="-fexceptions -sWASM_BIGINT" \
-CXXFLAGS_SL="-fexceptions -sWASM_BIGINT" -j || { echo 'emmake make postgis failed' ; exit 442; }
+emmake make LDFLAGS_SL="-sWASM_BIGINT -sSIDE_MODULE=1 -fexceptions -Wl,--whole-archive -lgeos_c -Wl,--no-whole-archive -lstdc++ -lsqlite3 -lgeos -flto" \
+CFLAGS_SL="-fexceptions -sWASM_BIGINT -Oz -flto -ffunction-sections -fdata-sections" \
+CXXFLAGS_SL="-fexceptions -sWASM_BIGINT -Oz -flto -ffunction-sections -fdata-sections" -j || { echo 'emmake make postgis failed' ; exit 442; }
+/emsdk/upstream/bin/wasm-opt -Oz postgis/postgis-3.so -o postgis/postgis-3.opt.so || { echo 'wasm-opt postgis failed' ; exit 443; }
+mv postgis/postgis-3.opt.so postgis/postgis-3.so
 # emmake make PG_LDFLAGS="-L/install/libs/lib -lpgport -lpgcommon -sSIDE_MODULE=1" -j
 
 cd ..