diff --git a/include/fmt/core.h b/include/fmt/core.h
index 834b2d57..8d53d86a 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -1947,7 +1947,7 @@ template <typename Char> class specs_setter {
   FMT_CONSTEXPR void on_localized() { specs_.localized = true; }
 
   FMT_CONSTEXPR void on_zero() {
-    specs_.align = align::numeric;
+    if (specs_.align == align::none) specs_.align = align::numeric;
     specs_.fill[0] = Char('0');
   }
 
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 4dc9e097..60a1b559 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -1588,13 +1588,17 @@ FMT_CONSTEXPR OutputIt write(OutputIt out, const Char* s,
 
 template <typename Char, typename OutputIt>
 OutputIt write_nonfinite(OutputIt out, bool isinf,
-                         const basic_format_specs<Char>& specs,
+                         basic_format_specs<Char> specs,
                          const float_specs& fspecs) {
   auto str =
       isinf ? (fspecs.upper ? "INF" : "inf") : (fspecs.upper ? "NAN" : "nan");
   constexpr size_t str_size = 3;
   auto sign = fspecs.sign;
   auto size = str_size + (sign ? 1 : 0);
+  // Replace '0'-padding with space for non-finite values.
+  const bool is_zero_fill =
+      specs.fill.size() == 1 && *specs.fill.data() == static_cast<Char>('0');
+  if (is_zero_fill) specs.fill[0] = static_cast<Char>(' ');
   return write_padded(out, specs, size, [=](reserve_iterator<OutputIt> it) {
     if (sign) *it++ = static_cast<Char>(data::signs[sign]);
     return copy_str<Char>(str, str + str_size, it);
diff --git a/test/format-test.cc b/test/format-test.cc
index cbed4984..38399788 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -1272,10 +1272,16 @@ TEST(format_test, format_nan) {
   double nan = std::numeric_limits<double>::quiet_NaN();
   EXPECT_EQ("nan", fmt::format("{}", nan));
   EXPECT_EQ("+nan", fmt::format("{:+}", nan));
-  if (std::signbit(-nan))
+  EXPECT_EQ("  +nan", fmt::format("{:+06}", nan));
+  EXPECT_EQ("+nan  ", fmt::format("{:<+06}", nan));
+  EXPECT_EQ(" +nan ", fmt::format("{:^+06}", nan));
+  EXPECT_EQ("  +nan", fmt::format("{:>+06}", nan));
+  if (std::signbit(-nan)) {
     EXPECT_EQ("-nan", fmt::format("{}", -nan));
-  else
+    EXPECT_EQ("  -nan", fmt::format("{:+06}", -nan));
+  } else {
     fmt::print("Warning: compiler doesn't handle negative NaN correctly");
+  }
   EXPECT_EQ(" nan", fmt::format("{: }", nan));
   EXPECT_EQ("NAN", fmt::format("{:F}", nan));
   EXPECT_EQ("nan    ", fmt::format("{:<7}", nan));
@@ -1288,6 +1294,11 @@ TEST(format_test, format_infinity) {
   EXPECT_EQ("inf", fmt::format("{}", inf));
   EXPECT_EQ("+inf", fmt::format("{:+}", inf));
   EXPECT_EQ("-inf", fmt::format("{}", -inf));
+  EXPECT_EQ("  +inf", fmt::format("{:+06}", inf));
+  EXPECT_EQ("  -inf", fmt::format("{:+06}", -inf));
+  EXPECT_EQ("+inf  ", fmt::format("{:<+06}", inf));
+  EXPECT_EQ(" +inf ", fmt::format("{:^+06}", inf));
+  EXPECT_EQ("  +inf", fmt::format("{:>+06}", inf));
   EXPECT_EQ(" inf", fmt::format("{: }", inf));
   EXPECT_EQ("INF", fmt::format("{:F}", inf));
   EXPECT_EQ("inf    ", fmt::format("{:<7}", inf));